Packet communication between two endpoints in different packet communities has been the topic of much research and patent activity. For purposes of this patent, "packet communities" are any set of systems that communicate with each other by packets. A packet switch or a local area network (LAN) are just two examples of "packet communities." An "endpoint" is a device on a packet switch or a node on a LAN that is a source or destination of packet traffic. Communication between two endpoints in different packet communities is therefore sending packets between one device connected to a first packet switch (or one node on a first LAN) to a second device on a different packet switch (a second node on a second LAN).
The disclosure of U.S. Pat. No. 5,144,622, which issued in the name of Takiyasu, et al., on Sep. 1, 1992, (herein Takiyasu) describes a system for interconnecting LANs to provide packet communication from a node on a first LAN to a node on a second LAN. In this system, a packet sent from a source node on a first LAN is received at a LAN interconnection switching unit, which is also on the LAN. The LAN interconnection switching unit determines that the destination for the packet is not on the LAN, and places the packet in memory. The LAN interconnection switching unit performs a search of its own records of routing information to determine a route for the packets. The LAN interconnection switching unit then sends a call set up message to all LAN interconnection switching units in the path to the destination LAN to alert them of the pending transmission. The LAN interconnection switching unit then transmits the packets to the destination LAN via the intermediate LAN interconnection switching units. The destination LAN interconnection switching unit receives the packets and sends the packets out on the second LAN.
The system of Takiyasu, while sufficient for some purposes, is weak in two basic arc as. First, the system requires that each of the LAN interconnection switching units has all of the routing table information for the entire interconnected system. These tables are hard to maintain because they all have to be changed whenever any alteration of the network occurs. Second, the system is slow in delivering the initial several packets, for at least the time it takes to calculate a route and send the routing message through the network by the calculated route.
Therefore, a problem in the art is a lack of fast, easy to maintain inter-packet community packet communication system.